[PATCH v5 01/18] watchdog/perf: Define dummy watchdog_update_hrtimer_threshold() on correct config

Douglas Anderson dianders at chromium.org
Sat May 20 03:18:25 AEST 2023

The real watchdog_update_hrtimer_threshold() is defined in
kernel/watchdog_hld.c. That file is included if
CONFIG_HARDLOCKUP_DETECTOR_PERF and the function is defined in that

The dummy version of the function in "nmi.h" didn't get that quite
right. While this doesn't appear to be a huge deal, it's nice to make
it consistent.

It doesn't break builds because CHECK_TIMESTAMP is only defined by
x86 so others don't get a double definition, and x86 uses perf lockup
detector, so it gets the out of line version.

Fixes: 7edaeb6841df ("kernel/watchdog: Prevent false positives with turbo modes")
Reviewed-by: Nicholas Piggin <npiggin at gmail.com>
Reviewed-by: Petr Mladek <pmladek at suse.com>
Signed-off-by: Douglas Anderson <dianders at chromium.org>

Changes in v5:
- Add Nicholas's explanation of why this didn't break builds.
- watchdog_hardlockup_perf.c => kernel/watchdog_hld.c in description.

Changes in v4:
- ("Define dummy watchdog_update_hrtimer_threshold() ...") new for v4.

 include/linux/nmi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 048c0b9aa623..771d77b62bc1 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -197,7 +197,7 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh);
 void watchdog_update_hrtimer_threshold(u64 period);
 static inline void watchdog_update_hrtimer_threshold(u64 period) { }

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